Human milk galectin-3 binding protein and breast-feeding-associated HIV transmission.

Analysis of milk from 247 HIV-infected Zambian mothers showed that galectin-3 binding protein concentrations were significantly higher among HIV-infected mothers who transmitted HIV through breast-feeding (6.51 ± 2.12 µg/mL) than among nontransmitters but were also correlated with higher milk and plasma HIV RNA copies/mL and lower CD4+ cell counts. The association between galectin-3 binding protein and postnatal transmission was attenuated after adjustment for milk and plasma HIV load and CD4+ cell counts. This suggests that although milk galectin-3 binding protein is a marker of advanced maternal disease, it does not independently modify transmission risk.

HIV-1 concentrations in human breast milk before and after weaning.

Concentrations of HIV-1 RNA and DNA in mucosal compartments influence the risk of sexual transmission and mother-to-child transmission of HIV-1. Breast milk production is physiologically regulated such that supply is a function of infant demand, but whether demand also influences HIV-1 dynamics in breast milk is unknown. We tested whether minor and major changes in feeding frequency influence breast milk viral concentrations in 958 HIV-1-infected women and their infants followed, for 24 months during a trial in Lusaka, Zambia. Women were randomized to wean abruptly at 4 months or to continue breast-feeding for a duration of their own choosing. Two weeks after breast-feeding cessation (4.5 months), HIV-1 concentrations in breast milk were substantially higher (median RNA, 2708 copies/ml; DNA, 14 copies/ml) than if breast-feeding continued (median RNA, <50 copies/ml; DNA, <1 copy/ml; P < 0.0001). Among those continuing breast-feeding, HIV-1 concentrations in milk were higher if breast-feeding was nonexclusive (median RNA, 293 copies/ml; DNA, 2 copies/ml; P = 0.0006). Elevated milk viral concentrations after stopping breast-feeding explained higher than expected rates of late postnatal HIV transmission in those who weaned early. Changes in the frequency of breast-feeding peri-weaning and with nonexclusive breast-feeding influenced milk viral concentrations. This may explain the reduced risk of HIV-1 transmission associated with exclusive breast-feeding and why early weaning does not achieve the magnitude of HIV prevention predicted by models. Our results support continuation of maternal antiretroviral drug interventions over the full duration of time when any breast milk exposures may occur after planned weaning.

Coverage of primary mother-to-child HIV transmission isolates by second-generation broadly neutralizing antibodies.

OBJECTIVES AND DESIGN: A vaccine capable of providing cross-clade, sterilizing protection has been the holy grail of HIV-1 prevention and control since the beginning of the pandemic. A major component of this effort has been the identification and characterization of broadly neutralizing antibodies (bNAbs). Recent advances in bNAb isolation, structure-based engineering, and vector-mediated gene transfer have led to increased interest in bypassing the immune system by expressing neutralizing antibodies directly in muscle. To assess the neutralization potency and coverage of a panel of second-generation bNAbs, we cloned and phenotypically characterized 227 primary HIV-1 envelopes from 23 mother-to-child transmission (MTCT) pairs. METHODS: Viral envelopes were tested for in-vitro neutralization sensitivity using a standard pseudotype assay system. A 50% inhibitory concentration (IC50) at least 10 µg/ml was used to define neutralization resistance. RESULTS: The combination of antibodies PG16 and NIH45-46 had the broadest activity with the highest neutralization potency, achieving full coverage of 87% of transmission pairs (at a median sampling depth of 10 envelopes per pair) and 96% of recently infected infants in a very conservative analysis. CONCLUSIONS: Our data strongly support the inclusion of NIH45-46, or a more extensively modified variant, in future proof-of-principle immunoprophylaxis or gene therapy-based trials. Furthermore, until robust sequence-based resistance detection becomes available, it will be necessary to conduct deeper phenotypic screening of primary isolates in order to determine the prevalence of minor resistant variants to help in selecting the best reagents for clinical trials.

Dynamics of breast milk HIV-1 RNA with unilateral mastitis or abscess.

BACKGROUND: Mastitis and abscess in HIV-infected women increase the risk of breastfeeding transmission of HIV. Guidelines encourage women to stop breastfeeding on the affected breast and feed on the contralateral breast. However, impact of breast pathology on breast milk HIV dynamics is unknown. METHODS: HIV RNA was quantified in 211 breast milk samples collected before, during, and after a clinical mastitis or an abscess diagnosis from 38 HIV-infected women participating in a Zambian breastfeeding study. HIV RNA quantity was compared between affected and unaffected breasts over time using generalized estimating equation models. A sample of 115 women without breast pathology was selected as a control group. RESULTS: In the affected breast, breast milk HIV RNA quantity increased from the pre- to during-pathology period by log(10) 0.45 copies per milliliter [95% confidence interval (CI): 0.16 to 0.74], and after symptom resolution, HIV RNA levels were no different from prepathology levels (log10 -0.04 copies per milliliter 95% CI: -0.33 to 0.25). In the contralateral, unaffected breast, HIV RNA quantity did not significantly increase (log(10) 0.15 copies per milliliter, 95% CI: -0.41 to 0.10). Increase was more marked in women with abscess or with a greater number of mastitis symptoms. HIV RNA was not significantly different between affected and unaffected women, except at the time of diagnosis. CONCLUSIONS: Breast milk HIV RNA increased modestly in the affected breast with unilateral mastitis or abscess and returned to prepathology levels with symptom resolution. Contralateral HIV RNA was not affected. Results support guidelines encouraging feeding from the contralateral breast to minimize the risk of HIV transmission associated with unilateral breast pathology.

Pregnancy loss and role of infant HIV status on perinatal mortality among HIV-infected women.

BACKGROUND: HIV-infected women, particularly those with advanced disease, may have higher rates of pregnancy loss (miscarriage and stillbirth) and neonatal mortality than uninfected women. Here we examine risk factors for these adverse pregnancy outcomes in a cohort of HIV-infected women in Zambia considering the impact of infant HIV status. METHODS: A total of 1229 HIV-infected pregnant women were enrolled (2001-2004) in Lusaka, Zambia and followed to pregnancy outcome. Live-born infants were tested for HIV by PCR at birth, 1 week and 5 weeks. Obstetric and neonatal data were collected after delivery and the rates of neonatal (<28 days) and early mortality (<70 days) were described using Kaplan-Meier methods. RESULTS: The ratio of miscarriage and stillbirth per 100 live-births were 3.1 and 2.6, respectively. Higher maternal plasma viral load (adjusted odds ratio [AOR] for each log10 increase in HIV RNA copies/ml = 1.90; 95% confidence interval [CI] 1.10-3.27) and being symptomatic were associated with an increased risk of stillbirth (AOR = 3.19; 95% CI 1.46-6.97), and decreasing maternal CD4 count by 100 cells/mm3 with an increased risk of miscarriage (OR = 1.25; 95% CI 1.02-1.54). The neonatal mortality rate was 4.3 per 100 increasing to 6.3 by 70 days. Intrauterine HIV infection was not associated with neonatal morality but became associated with mortality through 70 days (adjusted hazard ratio = 2.76; 95% CI 1.25-6.08). Low birth weight and cessation of breastfeeding were significant risk factors for both neonatal and early mortality independent of infant HIV infection. CONCLUSIONS: More advanced maternal HIV disease was associated with adverse pregnancy outcomes. Excess neonatal mortality in HIV-infected women was not primarily explained by infant HIV infection but was strongly associated with low birth weight and prematurity. Intrauterine HIV infection contributed to mortality as early as 70 days of infant age. Interventions to improve pregnancy outcomes for HIV-infected women are needed to complement necessary therapeutic and prophylactic antiretroviral interventions.

Human milk oligosaccharide concentration and risk of postnatal transmission of HIV through breastfeeding.

BACKGROUND: The inefficiency of HIV breast-milk transmission may be caused by the presence of immunologically active factors, including human milk oligosaccharides (HMOs). OBJECTIVE: We investigated whether HMO concentrations are associated with a reduced risk of postnatal HIV transmission. DESIGN: A nested case-control study was conducted within a larger cohort study of HIV-infected women and their infants followed from birth to 24 mo in Lusaka, Zambia. Breast-milk samples collected at 1 mo from 81 HIV-infected women who transmitted via breastfeeding, a random sample of 86 HIV-infected women who did not transmit despite breastfeeding, and 36 uninfected breastfeeding women were selected. Total and specific HMO concentrations were measured by HPLC and compared between groups with adjustment for confounders by using logistic regression. RESULTS: HIV-infected women with total HMOs above the median (1.87 g/L) were less likely to transmit via breastfeeding (OR: 0.45; 95% CI: 0.21, 0.97; P = 0.04) after adjustment for CD4 count and breast-milk HIV RNA concentrations; a trend toward higher concentrations of lacto-N-neotetraose being associated with reduced transmission (OR: 0.49; 95% CI: 0.23, 1.04; P = 0.06) was also observed. The proportion of 3'-sialyllactose (3'-SL) per total HMOs was higher among transmitting than among nontransmitting women (P = 0.003) and correlated with higher plasma and breast-milk HIV RNA and lower CD4 counts. Neither Secretor nor Lewis status distinguished between transmitting and nontransmitting women. CONCLUSIONS: Higher concentrations of non-3'-SL HMOs were associated with protection against postnatal HIV transmission independent of other known risk factors. Further study of these novel, potentially anti-HIV components of breast milk is warranted.

'Worse than HIV' or 'not as serious as other diseases'? Conceptualization of cervical cancer among newly screened women in Zambia.

Invasive cervical cancer is the second most common cancer among women worldwide, with approximately 85% of the disease burden occurring in developing countries. To date, there have been few systematic efforts to document African women's conceptualization of cervical cancer after participation in a visual inspection with acetic acid (VIA)-based "see and treat" cervical cancer prevention program. In this study, conducted between September, 2009-July, 2010, focus groups and in-depth interviews were conducted with 60 women who had recently undergone cervical cancer screening at a government-operated primary health care clinic in Lusaka, Zambia. Interviewers elicited participants' causal representations of cervical cancer, associated physical signs and symptoms, perceived physical and psychological effects, and social norms regarding the disease. The lay model of illness causation portrayed by participants after recent exposure to program promotion messages departed in several ways from causal models described in other parts of the world. However, causal conceptualizations included both lay and biomedical elements, suggesting a possible shift from a purely traditional causal model to one that incorporates both traditional concepts and recently promoted biomedical concepts. Most, but not all, women still equated cervical cancer with death, and perceived it to be a highly stigmatized disease in Zambia because of its anatomic location, dire natural course, connections to socially-condemned behaviors, and association with HIV/AIDS. No substantive differences of disease conceptualization existed according to HIV serostatus, though HIV positive women acknowledged that their immune status makes them more aware of their health and more likely to seek medical attention. Further attention should be dedicated to the processes by which women incorporate new knowledge into their representations of cervical cancer.

Motivations and experiences of women who accessed "see and treat" cervical cancer prevention services in Zambia.

BACKGROUND: In Zambia, a country with a generalized HIV epidemic, age-adjusted cervical cancer incidence is among the highest worldwide. In 2006, the University of Alabama at Birmingham-Center for Infectious Disease Research in Zambia and the Zambian Ministry of Health launched a visual inspection with acetic acid (VIA) -based "see and treat" cervical cancer prevention program in Lusaka. All services were integrated within existing government-operated primary health care facilities. OBJECTIVE: Study aims were to (i) identify women's motivations for cervical screening, (ii) document women's experiences with screening and (iii) describe the potentially reciprocal influences between women undergoing cervical screening and their social networks. DESIGN AND METHODS: Focus group discussions (FGD) and in-depth interviews (IDI) were conducted with women who accepted screening and with care providers. Low-level content analysis was performed to identify themes evoked by participants. Between September 2009 and July 2010, 60 women and 21 care providers participated in 8 FGD and 10 IDI. RESULTS: Women presented for screening with varying needs and expectations. A majority discussed their screening decisions and experiences with members of their social networks. Key reinforcing factors and obstacles to VIA screening were identified. CONCLUSIONS: Interventions are needed to gain support for the screening process from influential family members and peers.

Exclusive breastfeeding, maternal HIV disease, and the risk of clinical breast pathology in HIV-infected, breastfeeding women.

OBJECTIVE: The objective of the study was to examine the relationship between breastfeeding patterns, markers of maternal human immunodeficiency virus (HIV) disease, and woman's breast pathology. STUDY DESIGN: Secondary data analysis from a randomized breastfeeding trial including 947 HIV-infected women (n = 5982 visits) from breastfeeding initiation until 6 months postpartum; 1 month after breastfeeding cessation; or loss to follow-up or death. Generalized estimating equations assessed the effects of breastfeeding pattern and maternal HIV status on breast pathology. RESULTS: One hundred ninety women (20.1%) had a breast problem; 86 (9.1%) had mastitis; and 31 (3.3%) had abscess. After confounder adjustment, nonexclusively breastfeeding women had an increased risk of breast problems (odds ratio, 1.98; 95% confidence interval, 1.33-2.95) and mastitis (odds ratio, 2.87, 95% confidence interval, 1.69-4.88) compared with exclusive breastfeeders. Women with a CD4 count less than 200 cells/µL tended to have an increased risk of abscess. CONCLUSION: Nonexclusive breastfeeding significantly increased the risk of breast pathology. Exclusive breastfeeding is not only optimal for infant health but it also benefits mothers by reducing breast problems.

Early weaning increases diarrhea morbidity and mortality among uninfected children born to HIV-infected mothers in Zambia.

BACKGROUND: Early weaning may reduce human immunodeficiency virus (HIV) transmission but may have deleterious consequences for uninfected children. Here we evaluate effects of early weaning on diarrhea morbidity and mortality of uninfected children born to HIV-infected mothers. METHODS: HIV-infected women in Lusaka, Zambia, were randomly assigned to breastfeeding for 4 months only or to continue breastfeeding until the mother decided to stop. Replacement and complementary foods were provided and all women were counseled around feeding and hygiene. Diarrhea morbidity and mortality were assessed in 618 HIV-uninfected singletons alive and still breastfeeding at 4 months. Intent-to-treat analyses and comparisons based on actual feeding practices were conducted using regression methods. RESULTS: Between 4 and 6 months, diarrheal episodes were 1.8-fold (95% confidence interval (CI), 1.3-2.4) higher in the short compared with long breastfeeding group. Associations were stronger based on actual feeding practices and persisted after adjustment for confounding. At older ages, only more severe outcomes, including diarrhea-related hospitalization or death (relative hazard [RH], 3.2, 95% CI, 2.1-5.1 increase 4-24 months), were increased among weaned children. CONCLUSIONS: Continued breastfeeding is associated with reduced risk of diarrhea-related morbidity and mortality among uninfected children born to HIV-infected mothers in this low-resource setting despite provision of replacement and complementary food and counseling. CLINICAL TRIALS REGISTRATION: NCT00310726.

Multiple independent lineages of HIV-1 persist in breast milk and plasma.

DESIGN: the origin and evolution of HIV-1 in breast milk is unclear, despite the continuing significance of this tissue as a transmitting compartment. To elucidate the evolutionary trajectory of viral populations in a transient mucosal compartment, longitudinal sequences of the envelope glycoprotein (gp120) region from plasma and breast milk spanning the first year after delivery were analyzed in six women infected by HIV-1 subtype C. METHODS: multiple phylogenetic algorithms were used to elucidate the evolutionary history and spatial structure of virus populations between tissues. RESULTS: overall persistent mixing of viral sequences between plasma and breast milk indicated that breast milk is not a distinct genetic viral compartment. Unexpectedly, longitudinal phylogenies showed multiple lineages defined by long branches that included virus from both the breast milk and the plasma. Plasma was unlikely the anatomical origin of the most recent common ancestor (MRCA) in at least three of the patients, although in other women, the temporal origin of the MRCA of the viral populations following delivery occurred well before the onset of breast milk production. CONCLUSIONS: these findings suggest that during pregnancy/lactation, a viral variant distinct from the plasma virus initially seeds the breast milk, followed by subsequent gene flow between the plasma and breast milk tissues. This study indicates the potential for reactivation or reintroduction of distinct lineages during major immunological disruptions during the course of natural infection.

Safety of artemether-lumefantrine in pregnant women with malaria: results of a prospective cohort study in Zambia.

BACKGROUND: Safety data regarding exposure to artemisinin-based combination therapy in pregnancy are limited. This prospective cohort study conducted in Zambia evaluated the safety of artemether-lumefantrine (AL) in pregnant women with malaria. METHODS: Pregnant women attending antenatal clinics were assigned to groups based on the drug used to treat their most recent malaria episode (AL vs. sulphadoxine-pyrimethamine, SP). Safety was assessed using standard and pregnancy-specific parameters. Post-delivery follow-up was six weeks for mothers and 12 months for live births. Primary outcome was perinatal mortality (stillbirth or neonatal death within seven days after birth). RESULTS: Data from 1,001 pregnant women (AL n = 495; SP n = 506) and 933 newborns (AL n = 466; SP n = 467) showed: perinatal mortality (AL 4.2%; SP 5.0%), comprised of early neonatal mortality (each group 2.3%), stillbirths (AL 1.9%; SP 2.7%); preterm deliveries (AL 14.1%; SP 17.4% of foetuses); and gestational age-adjusted low birth weight (AL 9.0%; SP 7.7%). Infant birth defect incidence was 1.8% AL and 1.6% SP, excluding umbilical hernia. Abortions prior to antenatal care could not be determined: abortion occurred in 4.5% of women treated with AL during their first trimester; none were reported in the 133 women exposed to SP and/or quinine during their first trimester. Overall development (including neurological assessment) was similar in both groups. CONCLUSIONS: These data suggest that exposure to AL in pregnancy, including first trimester, is not associated with particular safety risks in terms of perinatal mortality, malformations, or developmental impairment. However, more data are required on AL use during the first trimester.

Potential impact of new WHO criteria for antiretroviral treatment for prevention of mother-to- child HIV transmission.

We reviewed the potential impact of new WHO criteria for antiretroviral therapy using data from 1025 HIV-infected women and infants followed for 24 months in Lusaka, Zambia. The new criteria require initiating therapy among 68% of pregnant women and, if fully effective, would prevent 92% of maternal deaths and 88% of perinatal and postnatal infections. Using CD4 cell count below 350 cells/microl, irrespective of clinical stage, is more efficient and stricter CD4 cutoffs would be counter productive.

Methods and baseline results of a repeated cross-sectional survey to assess the public health impact of antiretroviral therapy in Lusaka, Zambia.

Although the individual-level impact of antiretroviral therapy (ART) is well documented, there are few available data describing the public health impact of services for persons infected with human immunodeficiency virus in resource-constrained settings. We describe the methods and baseline results of a household survey that assessed the population-level impact of the national program for HIV care in Zambia and treatment in the city of Lusaka. The survey was timed with the staggered expansion of services and repeated cross-sectional surveys planned for pre-implementation and post-implementation comparisons made by community. In the initial survey round, which was performed during the early phases of the program (November-December 2004), 18,110 persons were enumerated from 3,600 households surveyed. Respondents were asked questions designed to evaluate community-level mortality and respondent knowledge and attitudes towards HIV. These findings will serve as a reliable reference in the future analysis of the population-level impact of this HIV treatment and care program in Zambia.

Lactation-associated postpartum weight changes among HIV-infected women in Zambia.

BACKGROUND: There are concerns about effects of lactation on postpartum weight changes among HIV-infected women because low weight may increase risks of HIV-related disease progression. METHODS: This analysis of postpartum maternal weight change is based on a trial evaluating the effects of shortened breastfeeding on postpartum mother-to-child transmission of HIV in Lusaka, Zambia, in which 958 HIV-infected women were randomized to breastfeed for a short duration (4 months) or for a duration of their own informed choosing (median 16 months). Among 768 women who met inclusion criteria, we compared across the two groups change in weight (kg) and the percent underweight [body mass index (BMI) <18.5] through 24 months. We also examined the effect of breastfeeding in two high-risk groups: those with low BMI and those with low CD4 counts. RESULTS: Overall, women in the long-duration group gained less weight compared with those in the short-duration group from 4-24 months {1.0 kg [95% confidence interval (CI): 0.3-1.7] vs 2.3 kg (95% CI: 1.6-2.9), P = 0.01}. No association was found between longer breastfeeding and being underweight (odds ratio 1.1; 95% CI: 0.8-1.6; P = 0.40). Effects of lactation in underweight women and women with low CD4 counts were similar to the effects in women with higher BMI and higher CD4 counts. Women with low baseline BMI tended to gain more weight from 4 to 24 months than those with higher BMI, regardless of breastfeeding duration (2.1 kg, 95% CI: 1.3-2.9; P < 0.01). CONCLUSIONS: In this study of HIV-infected breastfeeding women in a low-resource setting, the average change in weight from 4 to 24 months postpartum was a net gain rather than loss. Although longer duration breastfeeding was associated with less weight gain, breastfeeding duration was not associated with being underweight (BMI < 18.5). Weight change associated with longer breastfeeding may be metabolically regulated so that women with low BMI and at risk of wasting are protected from excess weight loss.

Peripartum nevirapine exposure and subsequent clinical outcomes among HIV-infected women receiving antiretroviral therapy for at least 12 months.

OBJECTIVE: Prior exposure to intrapartum/neonatal nevirapine (NVP) is associated with compromised virologic treatment outcomes once non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy (ART) is initiated. We examined the longer-term clinical outcomes in a programmatic setting. METHODS: We compared post-12 month mortality and clinical treatment failure (defined by WHO clinical and immunologic criteria) among women with and without prior NVP exposure in Lusaka, Zambia. RESULTS: Between April 2004 and July 2006, 6740 women initiated an NNRTI-containing regimen. At 12 months, 5172 (78%) remained active and were included in this analysis. Of these, 596 (12%) reported prior NVP exposure, whose time from exposure to ART initiation was: <6 months for 11%, 6-12 months for 13%, >12 months for 37%, unknown for 39%. Overall, women with prior NVP exposure trended towards increased survival (adjusted hazard ratio [AHR]: 0.53; 95% confidence interval [CI]: 0.27-1.06, P = 0.07) and towards increased hazard of clinical treatment failure (AHR: 1.18; 95% CI: 0.95-1.47, P = 0.14), particularly those with exposure for <6 months (AHR: 1.52; 95% CI: 0.94-2.45, P = 0.09). CONCLUSIONS: Prior NVP exposure appeared to increase risk for clinical treatment failure after 12 months of follow-up, but this finding did not reach statistical significance. With growing evidence linking recent NVP exposure to virologic failure, optimized monitoring algorithms should be considered for women with starting NNRTI-based ART. The association between prior NVP exposure and improved survival has not been previously shown and may be a result of residual confounding around health-seeking behaviours.

Restriction of HIV-1 genotypes in breast milk does not account for the population transmission genetic bottleneck that occurs following transmission.

BACKGROUND: Breast milk transmission of HIV-1 remains a major route of pediatric infection. Defining the characteristics of viral variants to which breastfeeding infants are exposed is important for understanding the genetic bottleneck that occurs in the majority of mother-to-child transmissions. The blood-milk epithelial barrier markedly restricts the quantity of HIV-1 in breast milk, even in the absence of antiretroviral drugs. The basis of this restriction and the genetic relationship between breast milk and blood variants are not well established. METHODOLOGY/PRINCIPAL FINDINGS: We compared 356 HIV-1 subtype C gp160 envelope (env) gene sequences from the plasma and breast milk of 13 breastfeeding women. A trend towards lower viral population diversity and divergence in breast milk was observed, potentially indicative of clonal expansion within the breast. No differences in potential N-linked glycosylation site numbers or in gp160 variable loop amino acid lengths were identified. Genetic compartmentalization was evident in only one out of six subjects in whom contemporaneously obtained samples were studied. However, in samples that were collected 10 or more days apart, six of seven subjects were classified as having compartmentalized viral populations, highlighting the necessity of contemporaneous sampling for genetic compartmentalization studies. We found evidence of CXCR4 co-receptor using viruses in breast milk and blood in nine out of the thirteen subjects, but no evidence of preferential localization of these variants in either tissue. CONCLUSIONS/SIGNIFICANCE: Despite marked restriction of HIV-1 quantities in milk, our data indicate intermixing of virus between blood and breast milk. Thus, we found no evidence that a restriction in viral genotype diversity in breast milk accounts for the genetic bottleneck observed following transmission. In addition, our results highlight the rapidity of HIV-1 env evolution and the importance of sample timing in analyses of gene flow.

4E10-resistant HIV-1 isolated from four subjects with rare membrane-proximal external region polymorphisms.

Human antibody 4E10 targets the highly conserved membrane-proximal external region (MPER) of the HIV-1 transmembrane glycoprotein, gp41, and has extraordinarily broad neutralizing activity. It is considered by many to be a prototype for vaccine development. In this study, we describe four subjects infected with viruses carrying rare MPER polymorphisms associated with resistance to 4E10 neutralization. In one case resistant virus carrying a W680G substitution was transmitted from mother to infant. We used site-directed mutagenesis to demonstrate that the W680G substitution is necessary for conferring the 4E10-resistant phenotype, but that it is not sufficient to transfer the phenotype to a 4E10-sensitive Env. Our third subject carried Envs with a W680R substitution causing variable resistance to 4E10, indicating that residues outside the MPER are required to confer the phenotype. A fourth subject possessed a F673L substitution previously associated with 4E10 resistance. For all three subjects with W680 polymorphisms, we observed additional residues in the MPER that co-varied with position 680 and preserved charged distributions across this region. Our data provide important caveats for vaccine development targeting the MPER. Naturally occurring Env variants described in our study also represent unique tools for probing the structure-function of HIV-1 envelope.

Couples' voluntary counselling and testing and nevirapine use in antenatal clinics in two African capitals: a prospective cohort study.

BACKGROUND: With the accessibility of prevention of mother to child transmission (PMTCT) services in sub-Saharan Africa, more women are being tested for HIV in antenatal care settings. Involving partners in the counselling and testing process could help prevent horizontal and vertical transmission of HIV. This study was conducted to assess the feasibility of couples' voluntary counseling and testing (CVCT) in antenatal care and to measure compliance with PMTCT. METHODS: A prospective cohort study was conducted over eight months at two public antenatal clinics in Kigali, Rwanda, and Lusaka, Zambia. A convenience sample of 3625 pregnant women was enrolled. Of these, 1054 women were lost to follow up. The intervention consisted of same-day individual voluntary counselling and testing (VCT) and weekend CVCT; HIV-positive participants received nevirapine tablets. In Kigali, nevirapine syrup was provided in the labour and delivery ward; in Lusaka, nevirapine syrup was supplied in pre-measured single-dose syringes. The main outcome measures were nurse midwife-recorded deliveries and reported nevirapine use. RESULTS: In eight months, 1940 women enrolled in Kigali (984 VCT, 956 CVCT) and 1685 women enrolled in Lusaka (1022 VCT, 663 CVCT). HIV prevalence was 14% in Kigali, and 27% in Lusaka. Loss to follow up was more common in Kigali than Lusaka (33% vs. 24%, p = 0.000). In Lusaka, HIV-positive and HIV-negative women had significantly different loss-to-follow-up rates (30% vs. 22%, p = 0.002). CVCT was associated with reduced loss to follow up: in Kigali, 31% of couples versus 36% of women testing alone (p = 0.011); and in Lusaka, 22% of couples versus 25% of women testing alone (p = 0.137). Among HIV-positive women with follow up, CVCT had no impact on nevirapine use (86-89% in Kigali; 78-79% in Lusaka). CONCLUSIONS: Weekend CVCT, though new, was feasible in both capital cities. The beneficial impact of CVCT on loss to follow up was significant, while nevirapine compliance was similar in women tested alone or with their partners. Pre-measured nevirapine syrup syringes provided flexibility to HIV-positive mothers in Lusaka, but may have contributed to study loss to follow up. These two prevention interventions remain a challenge, with CVCT still operating without supportive government policy in Zambia.

Elevations in mortality associated with weaning persist into the second year of life among uninfected children born to HIV-infected mothers.

BACKGROUND: Early weaning has been recommended to reduce postnatal human immunodeficiency virus (HIV) transmission. We evaluated the safety of stopping breast-feeding at different ages for mortality of uninfected children born to HIV-infected mothers. METHODS: During a trial of early weaning, 958 HIV-infected mothers and their infants were recruited and followed up from birth to 24 months postpartum in Lusaka, Zambia. One-half of the cohort was randomized to wean abruptly at 4 months, and the other half of the cohort was randomized to continue breast-feeding. We examined associations between uninfected child mortality and actual breast-feeding duration and investigated possible confounding and effect modification. RESULTS: The mortality rate among 749 uninfected children was 9.4% by 12 months of age and 13.6% by 24 months of age. Weaning during the interval encouraged by the protocol (4-5 months of age) was associated with a 2.03-fold increased risk of mortality (95% confidence interval [CI], 1.13-3.65), weaning at 6-11 months of age was associated with a 3.54-fold increase (95% CI, 1.68-7.46), and weaning at 12-18 months of age was associated with a 4.22-fold increase (95% CI, 1.59-11.24). Significant effect modification was detected, such that risks associated with weaning were stronger among infants born to mothers with higher CD4(+) cell counts (>350 cells/microL). CONCLUSION: Shortening the normal duration of breast-feeding for uninfected children born to HIV-infected mothers living in low-resource settings is associated with significant increases in mortality extending into the second year of life. Intensive nutritional and counseling interventions reduce but do not eliminate this excess mortality.